下拉列表：二级联动菜单
Select对象的常用属性
options[]：返回所有option组成的一个数组；
name：名称
value：option的value的值
length：设置或读取option的个数
selectedIndex：当前选中的option的索引号
option对象的常用属性
text：指<option></option>中的文本
value：指option对象的value属性
index：指每个option对象的索引号
selected：当前option是否选中
代码部分
<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8" /> <title>form表单之select操作</title> <script type="text/javascript"> var arr_da = ["请选择大类目","1","2","3","4","5","6","7"]; var arr_xiao = [ ["请选择小类目"], ['101','102','103','104','105','106','107','108'], ['201','202','203','204','205','206','207','208'], ['301','302','303','304','305','306','307','308'], ['401','402','403','404','405','406','407','408'], ['501','502','503','504','505','506','507','508'], ['601','602','603','604','605','606','607','608'], ['701'] ]; onload = function() { var oForm = document.getElementById('form1'); var oda_da = document.getElementById('da'); var oxiao_xiao = document.getElementById('xiao'); /* var oda_da = oForm.children[2]; var oyyxm_yyxm = oForm.children[3]; */ // 添加点击 onchange 事件 oda_da.onchange = function() { var _this = this.selectedIndex; // 默认进来高度清零 oxiao_xiao.length = 0; // 指定下拉的高度 initxianz(_this); }; // 初始化下拉列表 init(); // init select function init(){ var index = 0; // 指定下拉的高度 oda_da.length = arr_da.length; // 循环数组, 把内容写到下拉列表中去 for( var i = 0; i < arr_da.length; i++ ){ oda_da.options[i].text = arr_da[i]; oda_da.options[i].value = arr_da[i]; } // 指定默认索引号 oda_da.selectedIndex = index; // 指定下拉的高度 initxianz(index); } //下拉内容高度 function initxianz(index){ // 指定下拉的高度 oxiao_xiao.length = arr_xiao[index].length; // 循环数组, 把内容写到下拉列表中去 for( var i = 0; i < arr_xiao[index].length; i++ ){ oxiao_xiao.options[i].text = arr_xiao[index][i]; oxiao_xiao.options[i].value = arr_xiao[index][i]; } } }; </script> </head> <body> <form id="form1" onSubmit="return xxg();"> 大分类: <select name="da" id="da" style="130px;"></select> 小分类: <select name="xiao" id="xiao" style="130px;"></select> <input type="submit" id="submit" class="nr_submit" value="提交预约" /> </form> <!--弹出测试--> <script> function xxg(){ var da = form1.da.value; var xiao = form1.xiao.value; } </script> <!--弹出测试结束--> </body> </html>